Combined crank and counterweight



May 3, 1938. K, R, JENSEN 2,115,814

COMBINED CRANK AND COUNTERWEIGHT Filed Dec. 50, 1937 Patented May 3, 1938 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to counterweights in connection with crank shafts.

An object of the invention is the provision of a counterweight adapted tobe applied to a crank with means for adjustably locking the counterweight either in a balanced or unbalanced position or in any of the intermediate positions between the balanced and unbalanced positions.

Another object of the invention is the provi- 10 sion of a counterweight adapted to be applied to a crank with a particular means for securely fastening the counterweight in a plurality of positions with respect to the crank whereby the counterweight may be revolved through an are of 180 and be retained in any degree desired throughout its 180 revolution.

A further object of the invention is the provision of a counterweight and a crank with a particular form of means for securing with facil- 5. ity the counterweight in any of a plurality of positions.

This invention will be best understood from a consideration of the following detailed description, in view of the accompanying drawing forming a part of the specification; nevertheless, it is to be understood that the invention is not confined to the disclosure, being susceptible of such changes and modifications as define no material departure from the salient features of the invention as expressed in the appended claims.

In the drawing:

Figure 1 is a side view in elevation of acounterweight and crank showing the counterweight in a balanced position,

Figure 2 is a vertical section taken along the line 2-2 of Figure 1,

Figure 3 is a view in elevation of a counterweight constructed in accordance with the principles of my invention shown in detached relation to from a crank,

Figure 4 is a vertical section of the counterweight taken along the line 44 of Figure 3,

Figure 5 is a view in elevation of the crank per se showing a face which is opposite to that disclosed in Figure 1,

Figure 6 is a view in perspective of a wedge employed in clamping the counterweight to the crank, and Figure '7 is a view in perspective of the wedge shown in Fig. 8 but showing the opposite face of the wedge.

Referring more particularly to the drawing,

it designates generally a crank in the form of a 55 plate in circular form having cut-out portions H cal at the upper end at each side of a vertical passing through the axis of the disc.

A pair of fingers. 12 are formed by the cut-out portions PI and by a vertical cut l3. These fingers have aligned horizontal passages M which a are adapted to receive a belt for drawing the fingers toward each other 'for clam-ping the disc HI onto a drive shaft (not shown) when said drive shaft is received by an opening [5 formed at the inner end of the cut Hi. I A key-way I6 formed in the disc lfl'opens into the passage 15 and is adapted to receive a key carried by the shaft so; that when the bolt has been secured in place the fingers I 2 will be clamped onto the sha-cft and the key will lock the shaft to said 15 disc; 7

A portio-nof the disc, as shown at in Figs. I and 2 is enlarged so that in effect a ring is provided at the periphery of the disc having a greater thickness: than the body portion M of the disc.

'Ih-i'sface of the disc, as shown in Figs. I and 2', is provided with pockets 22 adapted to receive heads 23 of bolts Z'lwhich extend through passages 25 in the ring portion 21! of the disc at spaced intervals of approximately 120 apart, although a greater number of passages may be provided if desired. The opposite face of the disc is also provided with pocketszfi and these pockets are in alignment with the pockets- 22. Each of the last-mentioned pockets is provided with an inclined surface 21' for a purpose which will be presently explained.

Located centrally of the disc I l! and in a vertical line is an embossed portion through which extends a pair of passages 3| and 32. These passages, as shown in- Fig. 2', have tapered walls to receive the tapered end of a crank pin and the free end" of the. pin at this point is usually provided with a lock nut. for securing the disc l0 to said pin. The: passages 3i and 32? are upon opposite sides of the. center: of the disc so that when the disc is connected to the drive shaft at the passage 15 and revolved: thereby,said disc will act as a crank- A counterweight, generally designatedv by the numeral 35, has an eccentric opening 36 adapted to receive the periphery of the disc Ill. An annular rib 31 is formed at the periphery of the opening 36 of the counterweight and has inclined walls 38 and 39 on its opposite faces. The inclined walls 38 of the rib 31 are adapted to be engaged by pairs of lugs 40 and 4| which are located at opposite sides of the pockets 22 formed in one face of the disc.

A plurality of wedges 42 in the form of metal blocks are adapted to be received by the pockets 26 and the other face of the disc and each wedge has an inclined shoulder 43 adapted to engage the inclined wall 21 of the pocket 26 formed in the disc l0 and also the inclined face 39 of the counterweight 35. These wedges are provided with centrally disposed openings 45 through which the bolts 24 are adapted to pass so that when nuts 46 threaded onto said bolts are drawn up tight the inclined shoulders 43 and 43a on the wedges 22 will securely clamp the counterweight 35 onto the disc It].

It will be noted that the counterweight 35 is.

provided with a plurality of indicating marks 50 at spaced intervals and at the periphery of the opening 36 and these indications are numbered from zero to 10. It will be noted from Fig. 1'

that the zero indication is in vertical alignment and at the top in Fig. 1 when the counterweight 35 is in the balanced position. The disc has cooperating graduations.

It will be noted from Figs. 2 and '7 that each of the wedges is provided with a pocket 55 to receive the nut 46 on a bolt 24 and this pocket forms an enlarged open end for the opening 45 and is located at the outer face of each wedge.

When the crank disc l0 and the counterweight 35 are sold to a customer a pamphlet is attached thereto giving instructions to the purchaser how the counterweight 35 may be positioned to obtain certain results and these instructions refer to the dial on the counterweight and their numbers adjacent the a-ngularly disposed markings 50 adjacent the periphery of the opening 36 in said counterweight. A purchaser then will be able to set the counterweight 35 in the proper position and secure said counterweight in place on the disc by the tightening of the nuts 46 on the bolts 24. It will be seen by this construction that a simple and eflicient device is provided whereby the counterweight 35 may be positioned properly by loosening of the nuts 46 and then tightening said nuts after the counterweight has been set. The only requirement for setting the counterweight to give the best results will be the simple loosening of the bolts.

By the use of the adjustable counterbalance illustrated and described herein the counterbalance may be moved from balanced to the extreme unbalanced position, thereby enabling the operator to obtain the balance on the crank at various loads during reciprocating motion in which the cranks may be used singly or in multiples.

I claim:

1. A crank comprising a disc having an eccentric passage to receive a drive shaft, a circular counterweight having an eccentric opening receiving the periphery of the disc and provided with an annular rib at the periphery of the opening against which the periphery of the disc bears, said disc having spaced pockets at the periphery thereof and on opposite faces, wedges received in the pockets in one face and engaging the rib, headed bolts passing through the pockets and wedges, the heads of the bolts being seated in the pockets in the other face and nuts for drawing the bolts up tight to clamp the counterweight in an adjusted position on the disc.

2. A crank comprising a disc having an eccentric passage to receive a drive shaft, a circular counterweight having an eccentric opening receiving the periphery of the disc and provided with an annular rib at the periphery of the opening against which the periphery of the disc bears, said disc having spaced pockets at the periphery thereof and on opposite faces, wedges received in the pockets in one face and engaging the rib,

headed bolts passing through the pockets and wedges, the'heads of the bolts being seated in the pocketsin the other face and nuts for drawing the bolts up tight to clamp the counterweight in an adjusted position on the disc, the counterweight adjacent the periphery of the eccentric opening being provided with a graduated scale which cooperates with a point on the disc to determine the proper annular position of the counterweight on the disc to obtain a predetermined counterbalancing of the shaft.

3. A combined crank and adjustable counterweight comprising a counterweight having an eccentric opening, a disc received by said opening and having an eccentric opening to receive a drive shaft, said counterweight adapted to be revolved on the disc for adjustably positioning the counterweight on said disc, lugs on the disc engaging the counterweight at one face thereof, means engageable with the opposite face of the disc and counterweight, means for clamping the last-mentioned means against the disc and counterweight for drawing the counterweight tight against said disc, the counterweight and said disc having cooperating graduations for indicating varying conditions of counterbalancing between a zero positionand a point diametrically opposite the zero position, said disc having a split portion adjacent the eccentric opening therein, the split portion normally aligning with the zero indication on the counterweight.

4. A crank in the form of a disc having a portion of the periphery cut away at opposite sides of a diameter to provide clamping fingers, said fingers having an opening located eccentrically of the disc to receive a drive shaft, said disc having eccentrically disposed passages to receive a crank pin, a weighted ring having an eccentric opening, the periphery of said opening received by the periphery of the disc, said disc having the portion bordering the periphery raised above the main body portion of the disc, the raised portion having pockets in the opposite faces thereof, bolts provided with heads seated in the pockets in one face, wedges located in the pockets in the other face and engaging one face of the ring, means on the other face of the ring engaging the first-mentioned face of the disc, and nuts in the wedges for drawing up the bolts for causing the ring to be clamped to the disc.

KRESTEN R. JENSEN. 

